a(n) = [x^n] Product_{k=1..2*n} (x + (-1)^k * k).

A348024

a(n) = [x^n] Product_{k=1..2*n} (x + (-1)^k * k).

Terms

    a(0) =1a(1) =1a(2) =-13a(3) =-87a(4) =2609a(5) =34965a(6) =-1638841a(7) =-33411007a(8) =2128380881a(9) =58501278297

External references